Precipitation in Sun Valley tops that of 92% of U.S. towns: 53 inches a year
High summer brings afternoon highs near 81°. A year here swings 64° from midwinter lows to midsummer highs. By July afternoons alone, it runs cooler than 87% of U.S. towns. The outdoor season runs from May to September, with highs of 69–81°.
A year in Sun Valley at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sun Valley’s climate
Compared with towns across the U.S., with Sun Valley’s place in Pennsylvania beside it.
What a year in Sun Valley feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 153 frost-free days a year
In half of years the last 32° night comes by May 7 and the first by October 6. Frost and day counts come from NOAA’s station at Francis E Walter Dam, PA, 17 miles from the town’s center, 310 ft higher.
The 2023 USDA map puts Sun Valley’s center in zone 6b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −5°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 27 inches of snow a winter
Snow, measured at Lehighton 1ssw, PA, falls mostly in February. Precipitation (rain plus melted snow) adds up to 53 inches a year; September is the wettest month and February the driest. Rain or snow falls on about 132 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Sun Valley
95% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Francis E Walter Dam, PA.
Living with Sun Valley’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
153 frost-free days in zone 6b. The last frost comes by May 7 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 6.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September.
Parks & trails →Of the yearly building losses FEMA expects in Sun Valley from natural hazards, river flooding is the largest share (58%); heat waves, cold waves, winter storms and ice storms together are 24%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sun Valley and its neighbors
Indian Mountain Lake has the coldest January nights next door (15°, 2° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Sun Valley’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Sun Valley, PA | 17° | 81° | 53" | 27" |
| West Greenwich, RI | 20° | 82° | 51" | 35" |
| Thompson, CT | 18° | 82° | 50" | 39" |
| Carver, MA | 21° | 83° | 51" | 31" |
| North Berwick, ME | 13° | 81° | 49" | 39" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Sun Valley averaged 1.9° warmer than the 1900s. The biggest change is in December (+3.8°).
A bigger shift than in 86% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Sun Valley compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sun Valley’s place among Pennsylvania’s.
Sun Valley weather by month
Highs, lows and precipitation from NOAA’s grid at Sun Valley’s center; snow, wet days and snow on the ground from Lehighton 1ssw, PA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 34° | 17° | 3.9" | 7.8" | 11 | 16° – 33° |
| February | 37° | 19° | 3.0" | 9.8" | 9 | 15° – 35° |
| March | 45° | 25° | 4.2" | 6.3" | 10 | 29° – 46° |
| April | 59° | 35° | 4.3" | 0.4" | 11 | 42° – 52° |
| May | 69° | 45° | 4.3" | 0.0" | 14 | 52° – 63° |
| June | 76° | 54° | 5.3" | 0.0" | 13 | 62° – 69° |
| July | 81° | 59° | 4.9" | 0.0" | 12 | 66° – 74° |
| August | 79° | 57° | 4.8" | 0.0" | 11 | 64° – 71° |
| September | 72° | 50° | 5.5" | 0.0" | 10 | 58° – 65° |
| October | 61° | 39° | 5.0" | 0.0" | 11 | 45° – 58° |
| November | 49° | 31° | 3.8" | 0.3" | 10 | 35° – 45° |
| December | 38° | 23° | 4.4" | 2.7" | 11 | 22° – 42° |
| Year | 58° | 38° | 53.4" | 27.3" | 132 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 22° to 42°. September is the most reliable, staying within 7°.
Where Sun Valley’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Sun Valley’s center.
- Snow: Lehighton 1ssw, PA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Francis E Walter Dam, PA, 17 miles from the town’s center, 310 ft higher; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Sun Valley’s climate
What is the weather like in Sun Valley?
A typical July afternoon reaches 81°, a January night drops to 17°, and about 27 inches of snow falls in a normal winter. Colder January nights than 76% of U.S. towns; cooler July afternoons than 87% of U.S. towns.
How cold does it get in Sun Valley in winter?
January nights average 17°. About 163 nights a year reach 32° or below and 9 reach 0° or below. In the coldest January of the last 30 years the month averaged 16°.
How much snow does Sun Valley get?
About 27 inches in a normal winter at Lehighton 1ssw, PA, most of it in February.
How hot does it get in Sun Valley?
July, with a typical high of 81° and a low of 59°. About 4 days a year reach 90° (Francis E Walter Dam, PA).
When is the first and last frost in Sun Valley?
In half of years the last spring frost (32°) comes by May 7 and the first fall frost by October 6, about 153 frost-free days, at Francis E Walter Dam, PA.
What growing zone is Sun Valley in?
Zone 6b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −5°.
What is the best time of year to visit Sun Valley?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Sun Valley getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Sun Valley.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.